Tyche (Τύχη, meaning "luck" in Greek, Roman equivalent: Fortuna) was the presiding tutelary deity that governed the fortune and prosperity of a city, its destiny. She is the daughter of Hermes and Aphrodite.
Increasingly during the Hellenistic period, cities venerated their own specific iconic version of Tyche, wearing a mural crown (a crown like the walls of the city).
The Greek historian Polybius believed that when no cause can be discovered to events such as floods, drought or frosts then the cause of these events may be fairly attributed to Tyche.
Stylianos Spyridakis concisely expressed Tyche's appeal in a Hellenistic world of arbitrary violence and unmeaning reverses: "In the turbulent years of the Epigoni of Alexander, an awareness of the instability of human affairs led people to believe that Tyche, the blind mistress of Fortune, governed mankind with an inconstancy which explained the vicissitudes of the time."
In literature, she might be given various genealogies, as a daughter of Hermes and Aphrodite, or considered as one of the Oceanids, daughters of Oceanus and Tethys, or of Zeus. She was connected with Nemesis and Agathos Daimon ("good spirit").